It seems like half of the reviews out there are saying that at no point were they "scared" by this movie. The Exorcist was never about cheap jump scares or filling every minute with excitement. It was the story of a mother who didnt know what to do, a priest facing a crisis of faith, and a little girl who's having been possessed put everyone else through the emotional ringer. There were no jump scares. There was a lingering and ever present tension and unease, and the disgusting and vile displays of irreverance by the demon possessed Regan. I think that, while it didnt execute or pace everything perfectly, this movie stays true to the spirit of The Exorcist.
Nothing was dialed to 11 for the sake of the producers. Instead, this movie explores themes the the first didn't, like the existence of religions beyond modern Christianity . Could they have been more creative with the exorcism portion of the movie? Sure. But overall this movie was stressful, creepy, and upsetting (in a well done way) for anyone with children and therefore an understanding of how these parents would have been feeling.
I'd give this film a solid 7 out of 10. Room to improve for sure, but ultimately I enjoyed the experience as a horror enthusiast and a fan of the original movie and book.